The present invention relates to pull-type golf carts of the type used to carry a golf bag, together with clubs and related accessories. In particular, it relates to a motorized conversion system for making such pull-type golf carts self-propelled.
Pull-type golf carts are lightweight, two-wheeled carriages for holding and supporting a golf bag. Such carts have a handle at the forward end which is grasped by the user and pulled in a trailing manner. Most of the weight of the golf bag and clubs is supported by the cart wheels, which are mounted on opposite sides of a bag-carrying frame. When the cart is stopped, it is tilted upwardly and the base of the frame supporting the golf bag is set on the ground behind the wheels, forming a three point stand. Most golf carts are made of tubular steel or aluminum frame members. Portable carts, intended for easy transport, usually include some type of mechanism for collapsing the wheels and handle against the bag support frame to allow the cart to fit in the trunk of a car.
Several prior art systems have been developed for motorizing pull-type golf carts. Examples of systems which add a motor unit to a conventional golf cart are found in U.S. Pat. Nos. 3,719,247; 3,753,473; 3,941,198; 4,105,084; and 4,615,406. Examples of systems developed as dedicated motorized carts (i.e., not intended to be pulled by hand) are found in U.S. Pat. Nos. Des. 300,577 and 4,974,693.
One problem with the prior art systems for adding a motor to conventional pull-type golf carts is the complex and cumbersome procedures required to connect and disconnect the motorizing unit. For example, in U.S. Pat. No. 3,719,247, the power unit is suspended between the cart wheels and separate drive shafts must be connected to each of the cart wheels. U.S. Pat. Nos. 3,753,473 and 3,941,198 include multiple points of attachment between the add-on power unit and the cart, complicating attachment and detachment procedures. Prior art conversion systems also tend to be excessively heavy, incorporating pivoting or steerable drive wheels, as in U.S. Pat. Nos. 3,941,198 and 4,615,406, which add weight and complexity. Furthermore, most prior art add-on motorizing units interfere with the collapsibility of the cart and must be removed before the cart can be collapsed for transport and storage. Dedicated motorized golf bag carts tend to be even heavier and more cumbersome to dismantle and transport than carts with add-on motorizing units.
Since a golfer who owns a pull-type or motorized golf bag cart, and who plays at more than single golf course, will want to transport the cart from place to place, ease of transport is a important concern. It would be advantageous to have a power unit which can be quickly and easily added to a pull-type golf cart for motorizing the cart and which can also be collapsed against the cart for convenient transport.
It would be particularly advantageous to have a power unit for motorizing a pull-type golf cart which did not have to be removed each time the cart was collapsed for transport.
It would also be advantageous if such a power unit for motorizing a pull-type golf cart was relatively lightweight and simple to manufacture, install and use.
Accordingly, the invention provides a power unit for attachment to a non-motorized golf cart of the type having a pair of cart wheels, a handle for moving and steering the cart, and a bag support frame for holding a golf bag. The power unit comprises a leg for attachment to the bag support frame of the cart, and a releasable coupling for securing the leg to the bag support frame in a selection of orientations relative to the bag support frame. An electric motor and drive wheel assembly is supported on the leg. The drive wheel assembly includes a rotatable axle driven by the motor, and a pair of drive wheels attached to the axle. A battery support is attached to the leg for supporting a battery to energize the motor. And a motor controller is connected electrically to the motor and connectable to a battery for controlling the motor.
In its preferred form, the invention includes a single leg attached to the upper end of the golf cart frame, adjacent the point where the handle of the cart attaches to the frame. When the power unit is in its operable or "working" configuration (i.e., not collapsed), the leg extends downwardly at a large acute or perpendicular angle relative to the frame of the cart. The drive wheels mounted on the distil end of the leg, opposite the end attached to the golf cart frame, support the upper, front end of the cart and engage the ground to push or pull the cart along as the motor turns. The motor controller is affixed to the golf cart handle at a convenient location, providing selectable on/off, speed, and directional (i.e., forward/reverse) control. For transport, the releasable coupling between the leg and cart is loosened and the le is folded toward the frame into its collapsed configuration. In the collapsed configuration, the power unit is moved to a position against or adjacent the frame of the golf cart, in which the leg assumes a smaller acute or zero angle relative to the frame. In its collapsed configuration, the motor, wheels and other parts of the power unit are positioned close to the frame of the cart, with the power unit drive wheels nested between the cart wheels. The power unit need not be detached for transport, although the battery on the battery support is preferably removed. The unit does not appreciably interfere with the collapsibility of the cart wheels of a conventional, collapsible golf cart.